Enables frozen string in the following:

* ee/app/controllers/**/*.rb
* ee/app/finders/**/*.rb

Partially addresses gitlab-org/gitlab-ce/#47424.

CE upstream - 2018-11-23 18:21 UTC

See merge request gitlab-org/gitlab-ee!8579

Adds loading state to linked pipeline

See merge request gitlab-org/gitlab-ee!8572

# Conflicts:
#	doc/README.md

[ci skip]

CE upstream - 2018-11-23 15:21 UTC

See merge request gitlab-org/gitlab-ee!8574

Speed up setting of relative position

See merge request gitlab-org/gitlab-ee!8573

Speed up setting of relative position

See merge request gitlab-org/gitlab-ce!23324

Resolve "Filter by `None`/`Any` for labels in issues/mrs API"

Closes #52371

See merge request gitlab-org/gitlab-ce!22622

Add docs note for Reverting MR availability

See merge request gitlab-org/gitlab-ce!22289

add a note about omnibus chart and info how to backup with gitlab chart

See merge request gitlab-org/gitlab-ce!23097

CE port: Promote the GitLab.com Gold trial on a users default dashboard

See merge request gitlab-org/gitlab-ce!22901

EE: Promote the GitLab.com Gold trial on a users default dashboard

See merge request gitlab-org/gitlab-ee!8571

[docs] Enable importing from other sites

See merge request gitlab-org/gitlab-ce!23082

Fix container_scanning job link

See merge request gitlab-org/gitlab-ee!8577

Set content disposition attachment to several endpoints

See merge request gitlab-org/gitlab-ce!23223

Add instructions on how to add Prometheus as data source in Grafana

See merge request gitlab-org/gitlab-ce!23273

Replace public_jobs attribute with public_builds attribute in Projects API docs

See merge request gitlab-org/gitlab-ce!23194

Renders a loading spinner for the isLoading
state.
Updates tests

Add missing languages in Proofreaders page

See merge request gitlab-org/gitlab-ce!23243

Deploy cert-manager to managed cluster for SSL certificates

See merge request gitlab-org/gitlab-ce!23036

Refactor landing page EE

See merge request gitlab-org/gitlab-ee!8523

Refactor landing page CE

See merge request gitlab-org/gitlab-ce!23215

By using the parameters `?labels=None|Any` the user can filter
issues/mrs from the API that has `none/any` label.

Affected endpoints are:

- /api/issues
- /api/projects/:id/issues
- /api/groups/:id/issues
- /api/merge_requests
- /api/projects/:id/merge_requests
- /api/groups/:id/merge_requests

Fix 404ing links for NGINX ingress controller

See merge request gitlab-org/gitlab-ce!23258

Add additional requirements to Security Dashboard

See merge request gitlab-org/gitlab-ee!8494

Move links to HTTPS to avoid possible 503 errors in broken link checkers

See merge request gitlab-org/gitlab-ce!23313

refresh the path to performance bar in admin settings with the up-to-date value

See merge request gitlab-org/gitlab-ce!23316

update screenshot for request profiling token

See merge request gitlab-org/gitlab-ce!23317